Wind power is considered one of the cleanest, most environmentally friendly energy sources presently available, and wind turbines have gained increased attention in this regard. A modern wind turbine typically includes a tower, a generator, a gearbox, a nacelle, and a rotor including one or more rotor blades. The rotor blades capture kinetic energy from wind using known foil principles and transmit the kinetic energy through rotational energy to turn a shaft coupling the rotor blades to a gearbox, or if a gearbox is not used, directly to the generator. The generator then converts the mechanical energy to electrical energy that may be deployed to a utility grid.
During operation, the direction of the wind which powers the wind turbine may change. The wind turbine may thus adjust the nacelle through, for example, a yaw adjustment about a longitudinal axis of the tower to maintain alignment with the wind direction. In addition, the wind turbine may adjust a pitch angle of one or more of the rotor blades via a pitch drive mechanism configured with a pitch bearing to change the angle of the blades with respect to the wind.
Typical pitch drive mechanisms include pitch drive motor, a pitch drive gearbox, and a pitch drive pinion. In such configurations, the pitch drive motor is coupled to the pitch drive gearbox so that the pitch drive motor imparts mechanical force to the pitch drive gearbox. Similarly, the pitch drive gearbox may be coupled to the pitch drive pinion for rotation therewith. The pitch drive pinion may, in turn, be in rotational engagement with the pitch bearing coupled between the hub and a corresponding rotor blade such that rotation of the pitch drive pinion causes rotation of the pitch bearing. Thus, in such embodiments, rotation of the pitch drive motor drives the pitch drive gearbox and the pitch drive pinion, thereby rotating the pitch bearing and the rotor blade about the pitch axis.
During normal operation, the pitch drive motors are driven by the power grid. However, in some instances, such as during an adverse grid event, the pitch drive motors may be driven by one or more backup batteries. If pitching of the blades relies on such batteries (i.e. due to a grid loss), it is important to ensure that the batteries are capable of operating when needed. Overtime, however, the motor batteries of the pitch drive mechanisms lose their charge and eventually die. Thus, if such batteries die without notice, the rotor blade associated with the dead batteries may become stuck since there is no power available to pitch the blade. In such instances, loads may increase on the stuck rotor blade, thereby causing damage thereto.
As such, a predictive maintenance system and method that addresses the aforementioned issues would be desired. Accordingly, the present disclosure is directed to systems and methods for estimating the consumed battery life of the pitch system of the wind turbine based on temperature.